I've been trying to do some point analysis on some xyz data, I'm at the point where I've decided it is best to produce a boundary of my xyz files and put this with the metadata for each survey.

Now the part im stuck on is I've got over 15,000 surveys to compute the boundary of, tried convex hull and concave hull with varying results. I can be fairly confident of the regular interval in my points for each survey, so I was thinking of a buffer merge op of point interval + 25%...

Works great for smaller amounts of data.
however it doesn't seem the most efficient way on the larger xyz data (still waiting on one to complete processing 15 minutes in ... 500,000 points.).

1 Answer
1

Here is a solution which is running quite fast (around 15 seconds for a 5 million random points which i created for Texas State). I normalized the multipoint input and it is giving satisfactory output. I am using Topology Framework .NET. It is similar to NetTopologySuite. Maybe you can do the same with NetTopologySuite as well.

My solution (console application) is below. You may need to alter it for batch-running from folders.

Thanks I will give it a shot, I've experienced strange results when using convex hull, can you explain the multiPoint.Normalize() method and its purpose?
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JamoJun 6 '12 at 1:09

@Jamo sincerely..i don't know what it does..interesting thing is that when i loaded these 5 million points into the JTS Test-builder application as an xml test case, it generated the convex-hull in two seconds!!
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vinayanJun 6 '12 at 1:56